The goal of this Mentored Patient-Oriented Research Career Development Award is to allow the applicant to develop the clinical research skills needed to pursue an independent, productive career in rehabilitation research. The applicant is a licensed physical therapist with a clinical doctorate completing her postdoctoral training in clinical investigation. This award will enhance the applicant's ability to investigate mechanisms underlying pre-arthritic hip disease (PAHD) by combining the applicant's existing expertise in musculoskeletal disorders with additional training in the kinematic assessment of lower extremity movement and advanced methods in patient-oriented research. The long-term objective is to develop effective rehabilitation strategies for people with PAHD that will prevent or delay the need for surgical or pharmacological intervention. The specific aims of the proposed studies are designed to test the overall hypothesis that abnormal movement patterns contribute to the onset and persistence of PAHD. The proposed studies will 1) determine musculoskeletal differences between people with PAHD and people without PAHD, 2) determine the association among lower extremity movement patterns, muscle strength, bony abnormalities and self-report measures of functional ability, and 3) obtain preliminary data on the effectiveness of movement pattern training on measured impairments and functional ability in people with PAHD (exploratory treatment trial). People with PAHD and people without PAHD will participate in completing self-report measures of functional ability, tests of hip muscle strength, 3d movement assessment (kinematic) of specific functional movements and magnetic resonance imaging (MRI) to assess bony structure. Baseline data will be compared to determine if differences exist between people with PAHD and people without PAHD. To determine the best predictive variables of self- report functional ability, stepwise multivariable linear regression modeling will be used with the self-report measures as dependent variables and movement pattern abnormality, muscle strength and bony abnormalities as independent variables. Subjects with PAHD who wish to participate in a rehabilitation program will be provided motor pattern training including education to correct abnormal movement patterns during daily activities and strengthening of weak muscles thought to contribute to the abnormal movement patterns. Pretreatment and posttreatment measures will be compared to determine if improvements in impairments (abnormal movement pattern, muscle strength) correlate with an improvement in subjects' self-report of function. Results of this study will provide data to inform future mechanism-based studies of PAHD rehabilitation and injury prevention. In addition, data from the exploratory treatment trial will lead to a larger clinical trial to assess the effectiveness of movement pattern training.